Medical devices for use along the biliary and/or pancreatic tract

ABSTRACT

Medical devices and method for making and using the same are disclosed. An example medical device may include implantable medical device for use along the biliary and/or pancreatic tract. The implantable medical device may include a tubular member having a first end configured to be disposed within the duodenum of a patient and a second end configured to be disposed adjacent to a pancreatic duct and/or bile duct. The tubular member may have a body including one or more wire filaments that are woven together. The tubular member may also have an outer surface with a longitudinal channel formed therein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/192,660, filed Feb. 27, 2014, which claims priority under 35 U.S.C.§119 to U.S. Provisional Application Ser. No. 61/770,367, filed Feb. 28,2013, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure pertains to medical devices, and methods formanufacturing medical devices. More particularly, the present disclosurepertains to medical devices for draining body fluids along thepancreatic and/or biliary tract.

BACKGROUND

A wide variety of intracorporeal medical devices have been developed formedical use, for example, intravascular use. Some of these devicesinclude guidewires, catheters, and the like. These devices aremanufactured by any one of a variety of different manufacturing methodsand may be used according to any one of a variety of methods. Of theknown medical devices and methods, each has certain advantages anddisadvantages. There is an ongoing need to provide alternative medicaldevices as well as alternative methods for manufacturing and usingmedical devices.

BRIEF SUMMARY

This disclosure provides design, material, manufacturing method, and usealternatives for medical devices. An example medical device may includeimplantable medical device for use along the biliary and/or pancreatictract. The implantable medical device may include a tubular memberhaving a first end configured to be disposed within the duodenum of apatient and a second end configured to be disposed adjacent to apancreatic duct and/or bile duct. The tubular member may have a bodyincluding one or more wire filaments that are woven together. Thetubular member may also have an outer surface with a longitudinalchannel formed therein.

Another example implantable medical device for use along the pancreatictract may include a braided stent having a first end configured to bedisposed within the duodenum of a patient and a second end configured tobe disposed adjacent to a pancreatic duct so as to drain fluid. Thebraided stent may have an outer surface with a longitudinal channelformed therein. The longitudinal channel may be configured to drainfluid from branches of the pancreatic duct.

An example method for draining fluids along the biliary and/orpancreatic tract may include providing an implantable medical device.The implantable medical device may include a braided stent having afirst end configured and a second end. The braided stent may have anouter surface with a longitudinal channel formed therein. The method mayalso include disposing the braided stent within a patient such that thefirst end is disposed within the duodenum and the second end extendswithin a region of the biliary and/or pancreatic tract, and drainingfluid from the region of the biliary and/or pancreatic tract.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present disclosure.The Figures, and Detailed Description, which follow, more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description in connection with the accompanyingdrawings, in which:

FIG. 1 is a schematic overview of the biliary and/or pancreatic tree.

FIG. 2 is a perspective view of an example stent configured to drainfluids along the biliary and/or pancreatic tract of a patient's body.

FIG. 3 is a perspective view of a portion of another example stent.

FIG. 4 is a perspective view of a portion of another example stent.

FIG. 5 is a perspective view of a portion of another example stent.

FIG. 6 is a side view of a portion of another example stent.

FIG. 7 is a side view of a portion of another example stent.

FIG. 8 is a perspective view of another example stent.

FIG. 9 is a perspective view of a portion of another example stent.

FIG. 10 is a perspective view of a portion of another example stent.

FIG. 11 is a perspective view of a portion of another example stent.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the invention tothe particular embodiments described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the disclosure.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the terms “about” may include numbers thatare rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include one or more particular features,structures, and/or characteristics. However, such recitations do notnecessarily mean that all embodiments include the particular features,structures, and/or characteristics. Additionally, when particularfeatures, structures, and/or characteristics are described in connectionwith one embodiment, it should be understood that such features,structures, and/or characteristics may also be used connection withother embodiments whether or not explicitly described unless clearlystated to the contrary.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

Embodiments of the present disclosure relate to medical devices andprocedures for accessing body lumens, and specifically, for drainingfluids from the pancreatic duct and/or the bile duct of the biliary treein a patient's body.

Endoscopic retrograde cholangiopancreatography (ERCP) is primarily usedto diagnose and treat conditions of the bile ducts, including, forexample, gallstones, inflammatory strictures, leaks (e.g., from trauma,surgery, etc.), and cancer. Through the endoscope, the physician can seethe inside of the stomach and the duodenum, and inject dies into theducts in the bile tree and pancreas so they can be seen on X-rays. Theseprocedures may necessitate gaining and keeping access to the biliaryduct, which may be technically challenging, may require extensivetraining and practice to gain proficiency, and may require one or moreexpensive tools in order to perform. Blockage of the biliary duct mayoccur in many of the disorders of the biliary system, including thedisorders of the liver, such as, primary schlerosing cholangitis, stoneformation, scarring in the duct, etc. This requires the need to drainblocked fluids from the biliary system, to treat the disorders. In manycases, the clinician places a fine needle through the skin of theabdomen and into the liver, advancing it into the bile duct. A drainagetube is then placed in the bile duct, which drains the blocked fluidsout of the biliary system.

During an ERCP procedure, a number of steps are typically performedwhile the patient is often sedated and anaesthetized. For example, anendoscope may be inserted through the mouth, down the esophagus, intothe stomach, through the pylorus into the duodenum, to a position at ornear the ampulla of Vater (the opening of the common bile duct andpancreatic duct). Due to the shape of the ampulla, and the angle atwhich the common bile and pancreatic ducts meet the wall of theduodenum, the distal end of the endoscope is generally placed just pastthe ampulla. Due to positioning of the endoscope beyond the ampulla, theendoscopes used in these procedures are usually side-viewing endoscopes.The side-viewing feature provides imaging along the lateral aspect ofthe tip rather than from the end of the endoscope. This allows theclinician to obtain an image of the medical wall of the duodenum, wherethe ampulla of Vater is located, even though the distal tip of theendoscope is beyond the opening.

FIG. 1 illustrates an overview of the biliary system or tree. Theampulla of Vater is located at the illustrated portion of the duodenum12. For the purpose of this disclosure, the ampulla of Vater 14 isunderstood to be of the same anatomical structure as the papilla ofVater. The ampulla of Vater 14 generally forms the opening where thepancreatic duct 16 and the bile duct 18 can empty into the duodenum 12.The hepatic ducts, denoted by the reference numeral 20, are connected tothe liver 22 and empty into the bile duct 18. Similarly, the cystic duct24, being connected to the gall bladder 26, also empties into the bileduct 18. In general, an endoscopic or biliary procedure may includeadvancing a medical device to a suitable location along the biliary treeand then performing the appropriate intervention.

Accessing a target along the biliary tree may often involve advancing anendoscope through the duodenum 12 to a position adjacent to the ampullaof Vater 14, and advancing a medical device, which may be a stent,through the endoscope and through the ampulla of Vater 14 to theintended target. The intended target may be, for example, the commonbile duct 18 and the pancreatic duct 16.

The present disclosure provides devices and methods for improving accessto various target locations along the biliary tree, and to drain fluidsalong a target location within the biliary tree of a patient's body. Forexample, these systems and methods may allow a medical device, such as astent, to easily access a particular target location along the biliaryand/or pancreatic tree and to drain a fluid from a target location.Furthermore, the systems and methods may allow a clinician to access atarget location, without the need to re-cannulate the ampulla of Vater14, the common bile duct 18, and/or the pancreatic duct 16. In addition,some portions of the biliary and/or pancreatic tree (e.g., thepancreatic duct) may be relatively highly branched. Some drainage stentsmay have a tendency to cover or other obstruct one or more of thebranches. At least some of the devices and methods disclosed herein mayinclude structural features that are designed to help provide drainageof both the main duct as well as drainage along one or more branches offof the main duct.

FIG. 2 illustrates a portion of an implantable medical device 200configured to be disposed along the biliary and/or pancreatic tree of apatient's body. As shown in FIG. 2, the implantable medical device 200includes may take the form of a stent 200. The stent 200 may vary inform. In general, the stent 200 may be configured as a drainage stent.In some embodiments, the stent 200 may be a braided or mesh tube and maybe configured to be inserted into a lumen of the biliary and/orpancreatic tree. In general, a first end 206 of the stent 200 may beflared and may be configured to be positioned into the duodenum of thepatient's body. Further, a second end 202 of the stent 200 is configuredto be positioned into/adjacent to the pancreatic duct or the biliaryduct of the patient's body. A central lumen may be defined in the stent200 that may be utilized to drain fluids from the pancreatic duct or thebiliary duct.

The stent 200 may have a stent body 210 formed from one or more wirefilaments 214. The wire filaments 214 may be wound in a manner that theyinterlace each other. In some embodiments, a single wire filament 214may be used to define the stent body 210. Alternatively, a plurality ofwire filaments 214 may be used to define the stent body 210. The singleor plurality of wire filaments 214 may be braided, interlaced, orotherwise woven into the desired pattern. In at least some embodiments,the stent body 210 and/or the wire filament(s) 214 may include a superelastic and/or shape memory material. For example, the stent body 210and/or the wire filament(s) 214 may include a nickel-titanium alloy.

The stent 200 may have multiple longitudinal channels 218 formed alongthe outer surface of the stent body 210. Each of the longitudinalchannels 218 may extend and run substantially along the longitudinallength of the stent body 210, between the first end 206 and the secondend 202. However, in certain embodiments, the channels 218 may alsoextend only partially along the longitudinal length of the stent 200. Asshown, four channels 218 may be provided along the stent body 210 of thestent 200. Other numbers of channels may also be utilized as disclosedherein. The shape of the channels 218 is depicted in the cross-sectionalview of the second end 202 of the stent 200 illustrated in the upperleft portion of FIG. 2. Each of the channels 218 may resemble a C-shapestructure, extending longitudinally along the stent 200. This is just anexample. Other suitable shapes for the channels 218 may also becontemplated, such as, rectangular, triangular or an irregular shape.Further, each channel 218 may extend radially inwards to a predetermineddepth, from the stent body 210 of the stent 200.

The channels 218 may be configured to drain fluid out of a constrictionportion of a target site (which may be the pancreatic duct 16 or thebile duct 18 shown in FIG. 1. More particularly, the channels 218 mayallow side branches off of the pancreatic duct 16 or the bile duct 18 tobe drained. For example, channels 218 may define a space between theouter surface of the stent body 210 and the body lumen where fluid maypass. Thus, fluid coming from side branches along the pancreatic and/orbile duct may flow into the channels 218, along the stent body 210, andultimately into the duodenum. This may include the fluid passing thoughopenings in the stent body 210 or along the channels 218 directly intothe duodenum.

Accessing a target location within the biliary and/or pancreatic treemay incorporate use of an endoscope to position the stent 200 at thetarget location. For example, an endoscope may be advanced into a bodylumen to a position adjacent to a target location. In certainembodiments, the target location may be the common bile duct 18 or thepancreatic duct 16 (shown in FIG. 1) of the biliary tree. Specifically,the endoscope may be advanced through the duodenum 12 to a positionadjacent to the ampulla of Vater 14. When so positioned, the stent 200may be passed through the endoscope towards the desired target.Depending on the location of the constricted area, the stent 200 may beadvanced through the endoscope so that the second end 202 of the stent200 is disposed along the constricted areas in the bile duct 18 and/orthe pancreatic duct 16 of the patient's body.

FIG. 3 illustrates a portion of another example stent 300 that may besimilar in form and function to other stents disclosed herein. Thisfigure illustrates another variation contemplated for the stentsdisclosed herein. For example, rather than being formed from a braid ormesh of wire filament(s), stent 300 may be formed from a tubular member310 such as a metallic and/or polymeric tube. Tubular member 310 may beformed by extruding, molding, casting, or in any other suitable manner.In at least some embodiments, the central lumen of the tubular member310 may have a shape corresponding to the outer profile of the tubularmember 310, as shown. A plurality of openings 322 may be formed in thetubular member 310. In at least some embodiments, the openings 322 maybe formed by laser cutting the tubular member 310. This is just anexample. Other methods may be used to form the openings 322. In someembodiments, the tubular member may lack openings 322. Stent 300 mayalso include a plurality of channels 318. The channels 318 may be used,for example, to aid in the drainage of side branches off of thepancreatic duct (and/or other ducts) in a manner similar to channels218.

Numerous other variations are contemplated for the stents disclosedherein. As alluded to above, the number of channels may vary. Forexample, FIG. 4 illustrates a stent 400 formed from one or more wirefilaments 414 and having end 402. In this example, the stent 400 hasthree channels 418 formed therein. Similarly, FIG. 5 illustrates stent500 including a stent body 510 formed from one or more wire filaments514. In this example, the stent 500 has two channels 518. Collectively,these figures illustrate that essentially any suitable number ofchannels may be utilized for the various stents disclosed hereinincluding one channel, two channels, three channels, four channels, fivechannels, six channels, seven channels, eight channels, or the like.

FIG. 6 illustrates a portion of another example stent 600 that may besimilar in form and function to other stents disclosed herein. Stent 600may include a stent body 610 formed from one or more wire filaments 614.This figure illustrates another variation contemplated for the stentsdisclosed herein. For example, in addition to the longitudinal channelsdisclosed herein, some stents like stent 600 may include one or moreradial and/or circumferential channels 630. Circumferential channels 630may provide another fluid path that allows fluids to travelcircumferentially about the stent body 610. For example, some branchducts may not completely align with the longitudinal channels 618 and,thus, in the absence of a circumferential channel 630 may not beefficiently drained. The presence of circumferential channels 630 mayallow for more side branches to have access to fluid pathways fordrainage. In doing so, fluid from the side branches may travel about thestent body 610 (via one of the circumferential channels 630) and intoone or more of the longitudinal channels 618. Thus, circumferentialchannels 630 may further enhance the ability of stent 600 to drainfluids from side branches (e.g., side branches from the pancreaticduct).

Some stents may include just longitudinal channels and some stents mayinclude just circumferential channels. However, combinations may also beutilized. For example, FIG. 7 illustrates stent 700 formed from one ormore wire filaments 714 and having outer surface 710. Stent 700 mayinclude one or more longitudinal channels 718 and one or morecircumferential channels 730. Channels 718/730 may aid in drainage offluids in a manner similar to other channels disclosed herein.

FIG. 8 illustrates a portion of another example stent 800 that may besimilar in to form and function to other stents disclosed herein. Stent800 may include a stent body 810 formed from one or more wire filamentssimilar to other stents disclosed herein and may include ends 802/806.Stent 800 may also include one or more channels 818.

Stent 800 may include a covering or coating 834 disposed over the stentbody 810. The coating 834 may be applied to the stent 800.Alternatively, the coating may take the form of a polymeric sleeve,film, sheath, or tube that is disposed over and attached to the stentbody 810. The coating 834 may have a plurality of openings 838 formedtherein (e.g., after application of the coating 834). In at least someembodiments, the openings 838 may substantially align with channels 818.This may allow fluid to flow through the openings 838 and into thechannels 818.

FIG. 9 illustrates a portion of another example stent 900 that may besimilar in form and function to other stents disclosed herein. Stent 900may include stent body 910. Coating 934 may be disposed on stent body910. Coating 934 may have openings 938 formed therein. Openings 938 maybe disposed along channels 918 formed in stent body 914. In thisexample, three channels 918 may be formed in stent body 910.Furthermore, FIG. 10 illustrates a portion of another example stent 1000that may be similar in form and function to other stents disclosedherein. Stent 1000 may include stent body 1010. Coating 1034 may bedisposed on stent body 1010. Coating 1034 may have openings 1038 formedtherein. Openings 1038 may be disposed along channels 1018 formed instent body 1010. In this example, four channels 1018 may be formed instent body 1010. Collectively, these figures helps to illustrate thatstents including a coating may also vary in the number of longitudinalchannels formed therein. Thus, any suitable number of channels may beutilized in stent 800/900/1000 and other stents disclosed herein.

FIG. 11 illustrates a portion of another example stent 1100 that may besimilar in form and function to other stents disclosed herein. Stent1100 may include stent body 1110. Coating 1134 may be disposed on stentbody 1110. Coating 1134 may have openings 1138 formed therein. Openings1138 may be disposed along channels 1118 formed in stent body 1110. Inthis example, four channels 1118 may be formed in stent body 1110. Inaddition to channels 1118, stent body 1110 may also include one or morecircumferential channels 1130. Collectively, channels 1118/1130 may aidin the drainage of fluid along the pancreatic and/or bile duct in amanner similar to other stents/channels disclosed herein.

The materials that can be used for the various components of stentsdisclosed herein may include those commonly associated with medicaldevices. For simplicity purposes, the following discussion makesreference to stent 200. However, this is not intended to limit thedevices and methods described herein, as the discussion may be appliedto other similar stents and/or components of stents or devices disclosedherein.

Stent 200 may be made from a metal, metal alloy, polymer (some examplesof which are disclosed below), a metal-polymer composite, ceramics,combinations thereof, and the like, or other suitable material. Someexamples of suitable polymers may include polytetrafluoroethylene(PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylenepropylene (FEP), polyoxymethylene (POM, for example, DELRIN® availablefrom DuPont), polyether block ester, polyurethane (for example,Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC),polyether-ester (for example, ARNITEL® available from DSM EngineeringPlastics), ether or ester based copolymers (for example,butylene/poly(alkylene ether) phthalate and/or other polyesterelastomers such as HYTREL® available from DuPont), polyamide (forexample, DURETHAN® available from Bayer or CRISTAMID® available from ElfAtochem), elastomeric polyamides, block polyamide/ethers, polyetherblock amide (PEBA, for example available under the trade name PEBAX®),ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE),Marlex high-density polyethylene, Marlex low-density polyethylene,linear low density polyethylene (for example REXELL®), polyester,polybutylene terephthalate (PBT), polyethylene terephthalate (PET),polytrimethylene terephthalate, polyethylene naphthalate (PEN),polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI),polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (for example, KEVLAR®), polysulfone,nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon),perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin,polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS50A), polycarbonates, ionomers, biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like.

Some examples of suitable metals and metal alloys include stainlesssteel, such as 304V, 304L, and 316LV stainless steel; mild steel;nickel-titanium alloy such as linear-elastic and/or super-elasticnitinol; other nickel alloys such as nickel-chromium-molybdenum alloys(e.g., UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY®C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys,and the like), nickel-copper alloys (e.g., UNS: N04400 such as MONEL®400, NICKELVAC® 400, NICORROS® 400, and the like),nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such asMP35-N® and the like), nickel-molybdenum alloys (e.g., UNS: N10665 suchas HASTELLOY® ALLOY B2®), other nickel-chromium alloys, othernickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-ironalloys, other nickel-copper alloys, other nickel-tungsten or tungstenalloys, and the like; cobalt-chromium alloys; cobalt-chromium-molybdenumalloys (e.g., UNS: R30003 such as ELGILOY®, PHYNOX®, and the like);platinum enriched stainless steel; titanium; combinations thereof; andthe like; or any other suitable material.

As alluded to herein, within the family of commercially availablenickel-titanium or nitinol alloys, is a category designated “linearelastic” or “non-super-elastic” which, although may be similar inchemistry to conventional shape memory and super elastic varieties, mayexhibit distinct and useful mechanical properties. Linear elastic and/ornon-super-elastic nitinol may be distinguished from super elasticnitinol in that the linear elastic and/or non-super-elastic nitinol doesnot display a substantial “superelastic plateau” or “flag region” in itsstress/strain curve like super elastic nitinol does. Instead, in thelinear elastic and/or non-super-elastic nitinol, as recoverable strainincreases, the stress continues to increase in a substantially linear,or a somewhat, but not necessarily entirely linear relationship untilplastic deformation begins or at least in a relationship that is morelinear that the super elastic plateau and/or flag region that may beseen with super elastic nitinol. Thus, for the purposes of thisdisclosure linear elastic and/or non-super-elastic nitinol may also betermed “substantially” linear elastic and/or non-super-elastic nitinol.

In some cases, linear elastic and/or non-super-elastic nitinol may alsobe distinguishable from super elastic nitinol in that linear elasticand/or non-super-elastic nitinol may accept up to about 2-5% strainwhile remaining substantially elastic (e.g., before plasticallydeforming) whereas super elastic nitinol may accept up to about 8%strain before plastically deforming. Both of these materials can bedistinguished from other linear elastic materials such as stainlesssteel (that can also can be distinguished based on its composition),which may accept only about 0.2 to 0.44 percent strain beforeplastically deforming.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy is an alloy that does not show anymartensite/austenite phase changes that are detectable by differentialscanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA)analysis over a large temperature range. For example, in someembodiments, there may be no martensite/austenite phase changesdetectable by DSC and DMTA analysis in the range of about −60 degreesCelsius (° C.) to about 120° C. in the linear elastic and/ornon-super-elastic nickel-titanium alloy. The mechanical bendingproperties of such material may therefore be generally inert to theeffect of temperature over this very broad range of temperature. In someembodiments, the mechanical bending properties of the linear elasticand/or non-super-elastic nickel-titanium alloy at ambient or roomtemperature are substantially the same as the mechanical properties atbody temperature, for example, in that they do not display asuper-elastic plateau and/or flag region. In other words, across a broadtemperature range, the linear elastic and/or non-super-elasticnickel-titanium alloy maintains its linear elastic and/ornon-super-elastic characteristics and/or properties.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy may be in the range of about 50 to about 60 weightpercent nickel, with the remainder being essentially titanium. In someembodiments, the composition is in the range of about 54 to about 57weight percent nickel. One example of a suitable nickel-titanium alloyis FHP-NT alloy commercially available from Furukawa Techno Material Co.of Kanagawa, Japan. Some examples of nickel titanium alloys aredisclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which areincorporated herein by reference. Other suitable materials may includeULTANIUM™ (available from Neo-Metrics) and GUM METAL™ (available fromToyota). In some other embodiments, a superelastic alloy, for example asuperelastic nitinol can be used to achieve desired properties.

In at least some embodiments, portions or all of stent 200 may also bedoped with, made of, or otherwise include a radiopaque material.Radiopaque materials are understood to be materials capable of producinga relatively bright image on a fluoroscopy screen or another imagingtechnique during a medical procedure. This relatively bright image aidsthe user of stent 200 in determining its location. Some examples ofradiopaque materials can include, but are not limited to, gold,platinum, palladium, tantalum, tungsten alloy, polymer material loadedwith a radiopaque filler, and the like.

In some embodiments, a degree of Magnetic Resonance Imaging (Mill)compatibility may be imparted into stent 200. For example, stent 200 maybe made of a material that does not substantially distort the image andcreate substantial artifacts (i.e., gaps in the image). Certainferromagnetic materials, for example, may not be suitable because theymay create artifacts in an Mill image. Stent 200 may also be made from amaterial that the MRI machine can image. Some materials that exhibitthese characteristics include, for example, tungsten,cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®,PHYNOX®, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g.,UNS: R30035 such as MP35-N® and the like), nitinol, and the like, andothers.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of thedisclosure. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. An implantable stent comprising: a tubular memberformed of a plurality of interwoven wire filaments extending from afirst end of the tubular member to a second end of the tubular member,the first end configured to be disposed within a duodenum of a patientand the second end configured to be disposed in a pancreatic duct orbile duct; wherein the tubular member has a circumferential outersurface, a circumferential inner surface, and a central longitudinalaxis extending through the tubular member; wherein the tubular memberincludes a plurality of longitudinal channels extending parallel to thecentral longitudinal axis; wherein the plurality of interwoven wirefilaments are displaced radially inward from the circumferential outersurface to form the longitudinal channels; wherein the tubular memberincludes a generally cylindrical body and a flared end region flaredradially outward from the generally cylindrical body to the first end ofthe tubular member; wherein each of the plurality of longitudinalchannels extends along the generally cylindrical body but does notextend along the flared end region.
 2. The implantable stent of claim 1,wherein the plurality of interwoven wire filaments are displacedradially inward from the circumferential inner surface at thelongitudinal channels.
 3. The implantable stent of claim 1, wherein thetubular member has a length measured from the first end to the secondend, wherein the plurality of longitudinal channels extend along only aportion of the length.
 4. The implantable stent of claim 1, wherein thegenerally cylindrical body extends to the second end of the tubularmember.
 5. The implantable stent of claim 1, further comprising acovering disposed about the tubular member.
 6. The implantable stent ofclaim 5, wherein the covering is a silicone coating disposed on theplurality of wire filaments.
 7. The implantable stent of claim 1,wherein the plurality of interwoven wire filaments are formed of ashape-memory material.
 8. The implantable stent of claim 1, wherein theplurality of interwoven wire filaments are formed of a nickel-titaniumalloy.
 9. The implantable stent of claim 1, wherein the plurality oflongitudinal channels consists of three longitudinal channels.
 10. Animplantable stent comprising: a tubular member having a first end and asecond end, the first end configured to be disposed within a duodenum ofa patient and the second end configured to be disposed in a pancreaticduct or bile duct, the tubular member including: a generally cylindricalbody having a circumferential outer surface and a circumferential innersurface, the generally cylindrical body extending to the second end ofthe tubular member; a flared end region flared radially outward from thegenerally cylindrical body to the first end of the tubular member;wherein the tubular member including the generally cylindrical body andthe flared end region are formed of a plurality of interwoven wirefilaments extending from the first end of the tubular body to the secondend of the tubular body; wherein the generally cylindrical body includesa plurality of longitudinal channels spaced circumferentially around thegenerally cylindrical body, the plurality of longitudinal channelsformed by displacing the plurality of interwoven wire filaments radiallyinward from the circumferential outer surface; wherein the flared endregion is devoid of the plurality of longitudinal channels; a coveringdisposed about the tubular member.
 11. The implantable stent of claim10, wherein the plurality of interwoven wire filaments are displacedradially inward from the circumferential inner surface at the pluralityof longitudinal channels.
 12. The implantable stent of claim 10, furthercomprising a covering disposed about the tubular member.
 13. Theimplantable stent of claim 12, wherein the covering is a siliconecoating disposed on the plurality of wire filaments.
 14. The implantablestent of claim 10, wherein the plurality of interwoven wire filamentsare formed of a shape-memory material.
 15. The implantable stent ofclaim 10, wherein the plurality of interwoven wire filaments are formedof a nickel-titanium alloy.
 16. The implantable stent of claim 10,wherein the plurality of longitudinal channels consists of threelongitudinal channels.
 17. A method of draining fluids along a biliaryand/or pancreatic tract of a patient, the method comprising: insertingan implantable stent within the patient, wherein the implantable stentcomprises: a tubular member having a first end and a second end, thetubular member including a flared end region at the first end and agenerally cylindrical body extending from the flared end region to thesecond end, wherein the tubular member including the generallycylindrical body and the flared end region are formed of a plurality ofinterwoven wire filaments extending from the first end of the tubularbody to the second end of the tubular body, wherein the generallycylindrical body includes a plurality of longitudinal channels spacedcircumferentially around the generally cylindrical body, wherein theflared end region is devoid of the plurality of longitudinal channels,the plurality of longitudinal channels formed by displacing theplurality of interwoven wire filaments radially inward from acircumferential outer surface of the generally cylindrical body;positioning the first end of the tubular body within a duodenum of thepatient and the second end of the tubular body with the biliary and/orpancreatic tract of the patient.
 18. The method of claim 17, wherein theplurality of interwoven wire filaments are displaced radially inwardfrom a circumferential inner surface at the plurality of longitudinalchannels.